Natural down is recognized as a highly desirable insulating medium for various goods such as clothes and sleeping bags. Its excellent insulating characteristics result from the loft or the interlocking of the down and feathers when it is collected as a body. The loft creates dead air space between the down and feathers, and the trapped air provides insulating characteristics which are highly effective under a wide range of temperatures. After prolonged use, the down retains its loft and stays in a fluffy condition without matting, collecting together or condensing. When compressed or deformed, the down will generally return to its original position. Because the down links together and does not lose its loft, the exterior appearance of the goods is smooth and soft to the touch.
Using natural down as insulation in goods also provides significant advantages during manufacturing of the goods. The feathers comprising the down are relatively light in weight and can easily be transported and carried in airstreams. As a consequence, when the goods are manufactured, the down can be readily blow injected in an airstream into insulating pockets sewn into the goods for the purpose of receiving the down. It is therefore relatively easy for the manufacturer to sew the insulating pockets, quickly inject them with a desired weight or volume of down and thereafter close the pockets to permanently retain the quantity of down therein.
Presently, the major disadvantages of natural down are its cost and its availability. Various synthetic materials have been developed and utilized as alternatives to down, but in the past, none of the synthetic fiber materials have achieved substantially all of the desirable features of down.
In the past, the most advantageous form for using synthetic or polyester fibers as insulating material has been in a garneted sheet. Garneted sheets are formed by first cutting individual fibers of extruded polyester material into specific desired lengths. Thereafter, the cut lengths are crimped or formed with a repeating S-shaped curve. The crimped lengths or staples are thereafter placed in a layer and the fibers of the crimped staples are disoriented until they interlink or overlap with their adjacent fibers. Thereafter, the layer of interlinked crimped fibers are sprayed with a resin material to connect the fibers at their points of contact. In this manner, the fibers are essentially held together as a relatively uniform layer of material having essentially the same density throughout. The myriad of interlinked fibers creates the dead air space which provides the insulating characteristic of the garneted material. The sheet of material retains its resiliency to deformation because of the connection of the interlinked fibers. After garneting, the sheets of material are rolled into rolls suitable for shipping.
The layers of garneted polyester material are assembled into goods by cutting one or more layers of the material in a desired shape and sewing the layers between two sheets of material from which the goods are made. This cutting and sewing process is relatively time consuming and can be somewhat awkward to accomplish when manufacturing the goods. The layers of garneted material do not always remain properly positioned within the pocket after use since the layers of material may shift somewhat or the edges may move somewhat, leaving the periphery of the pocket relatively free of insulation and creating a roughened exterior appearance in the goods.
Blow injecting sheets of garneted polyester material, or pieces torn from the sheets, has not been effectively achieved. The pieces torn from the sheets readily clog the tubes of the blow injection apparatus, and in general, create problems relating to accurately filling the insulation receiving pockets, securing a desired appearance and feel, and maintaining resiliency.
Polyester fibers can also be used in an ungarneted state as insulation. Ungarneted fibers are those which have been cut to the desired lengths and possibly crimped, but they are not connected in an interlinked manner in a layer or in any other configuration. Essentially, the staples are randomly loose. Ungarneted fibers do not provide significant loft or resiliency but instead lump and mat together and do not maintain a desired initial shape. Many other naturally occuring fibers such as cotton fibers, wool fibers and the like are also subject to the same disadvantages as ungarneted synthetic fiber material. For these reasons, ungarneted polyester fibers are generally not used in average quality or high quality goods.
The advantages of blow injecting polyester fiber material has been recognized in the prior art. This recognition, however, extends primarily to the shape of bodies of material which are first formed from ungarneted polyester fiber material and thereafter are sprayed with a bonding material to retain the shape. Since this procedure does not relate to the use of garneted polyester, it is undesirable for a number of reasons. The typical garment manufacturer is unable to produce or form bodies suitable for blow injecting since formation according to the prior art requires the use of many complicated procedures, such as the capabilities for forming ungarneted fibers into the desired bodies and for thereafter spraying them with resin material. Such capabilities usually require the use of expensive machinery.
It is usually more desirable for a manufacturer to obtain and work with garneted polyester material which has previously been formed in rolled sheets, since the rolls are more efficiently and economically transported and utilized. The garment manufacturer may also wish to blow inject a particular type of polyester fiber but selection is not possible if only a particular type of polyester has been pre-formed in bodies suitable for blow injecting.
The described features of the prior art relative to blow injecting insulating material in goods generally set forth a background for understanding the importance and significance of the present invention. It will be appreciated, however, that the various limitations, considerations and disadvantages present in the prior art can be more fully appreciated and recognized in light of the improvements and teachings of the present invention which is described next.